I don't know if any of our forum members own an f/2.8 lens in that focal length or not. Of course, the Minolta 300mm f/2.8G (D) SSM lens was the most desirable. But, they're pretty hard to come by now. Sony will be making it, too (see link above).

In addition to the Sigma and Tamron, you also see a Tokina 300mm f/2.8 pop up from time to time.

Thanks Jim!
i have done a little checking, and it's surprising that the 120/300 f/2.8 hadn't been created for Minolta. The reviews from Canon owners have been very enthusiastic regarding this lens, so why Sigma hasn't produced it for Minolta is puzzling. I just now emailed Sigma regarding the chances of them creating this lens for Minolta/Sony now that Sony has entered the DSLR market. Hopefully we will have this lens available for us in the future.
At $6000 for this lens, Sony is too steep for me.... Sigma and Tamron's prices are more affordable. I just may have to check out those teleconverters, or pray harder for good concert seats! LOL!